JPH09297623A - Voltage and current regulator circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transform a temperature compensated oscillator into an IC and to supply the stabilized voltage of high accuracy by controlling externally the on-off combinations of switches included in a switch group and therefore outputting the desired voltage or current. SOLUTION: The resistance value of a trimming circuit 24 can be varied by the ROM data given from an external memory, and the circuit 24 includes a resistance 28 and plural pairs of resistances 29 and switches 30 which are connected in parallel to each other in a ladder form between the resistance 28 and the ground. Then the open-close control of every switch 30 is carried out based on the ROM data, so that the desired voltage or current is outputted. In such a constitution, a temperature compensated oscillator can be miniaturized as an IC and also the variance of output voltage due to the manufacture error caused when the oscillator is transformed into an IC can be easily corrected. Thus, the stabilized voltage of high accuracy is supplied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage / current regulator circuit, and more particularly to a temperature compensated oscillator (TCO) which stabilizes the oscillation frequency of the oscillator against changes in ambient temperature by a compensation circuit, and further to the above TCO. The present invention relates to a voltage regulator circuit that can supply a stabilized voltage or current with high accuracy even when it is miniaturized by making it into an IC, and a TCO using the voltage regulator circuit.

[0002]

2. Description of the Related Art Generally, there are various external factors that affect the frequency stability of an oscillator, but the most important factor is temperature. A temperature-compensated crystal oscillator (TCXO) using a crystal oscillator will be described below as an example. That is, various methods have been proposed to eliminate the influence of the above temperature. One of them is to change the load capacitance of the crystal oscillator by a compensating circuit to obtain the desired oscillation frequency with respect to changes in ambient temperature. A temperature-compensated crystal oscillator (TCXO) that stabilizes to the deviation of is known. The basic configuration of a conventional temperature-compensated crystal oscillator (TCXO) is generated by a compensation circuit 1 by inserting a varactor diode (varicap) 2 in series with a crystal resonator 3 and an amplifier 4 as shown in FIG. A DC voltage is applied to the varicap. The capacitor 5 connected to the varactor diode 2 is a capacitor (capacitor) for adjusting the control sensitivity (AFC sensitivity). In addition, the compensation circuit 1 is
As shown in FIG. 5B, it is formed of a resistance circuit network including a plurality of thermistors R (T) and resistors R, and when the oscillation frequency of the crystal oscillator changes with temperature change, the change occurs at each temperature. The DC voltage is generated so that the capacitance of the varicap cancels out. The compensating circuit 1 corrects variations in temperature characteristics of the crystal and variations in other circuit elements by replacing each circuit element of the resistance network with each product so that the frequency deviation is equal to or less than a frequency deviation specified in a desired temperature range. It is common to adjust so that As the TCXO, as shown in FIG. 5, in addition to an indirect type in which a DC voltage change is simply generated by a thermistor and a compensating circuit such as a resistor, a parallel circuit of a thermistor and a capacitor is directly connected to a crystal oscillator in series. There is a direct type in which a high frequency current is directly connected to the compensating circuit, and the equivalent series capacitance is changed by changing the resistance of the thermistor depending on the temperature.

[0003]

However, as described above, in the direct type TCXO in which the parallel circuit of the thermistor and the capacitor is connected to the crystal unit, the temperature characteristic of the thermistor itself influences the temperature compensation characteristic. The temperature characteristics such as the B constant of the thermistor and the resistance value at room temperature are limited in the types of materials that can be obtained, so there are not so many types and it is possible to obtain a thermistor suitable for all error ranges of the crystal cut angle. is not. In addition, in order to suppress the frequency stability more severely and minutely, it is necessary to strictly select the value of the parallel capacitor and the value of the resistor connected in series or in parallel to the thermistor for sensitivity adjustment, increasing man-hours and yield rate. Was accompanied by the deterioration of. On the other hand, the indirect type TCXO is configured as shown in FIGS. 5 (a) and 5 (b), but the resistance circuit network of the compensation circuit 1 requires a considerable space, so that the size is reduced. There was a limit. That is, in the conventional indirect TCXO as well, in the resistance circuit network of the compensation circuit, each circuit constant of the resistance element is adjusted by replacing the resistance element itself and repeating the temperature test each time. The resistor must be arranged outside the IC so that the compensation circuit can be replaced, and as a result, miniaturization is hindered. Further, the work of replacing the resistance element is labor-intensive and inefficient as in the case of the direct type. Therefore, it has been proposed to realize an epoch-making miniaturization and adjustment efficiency by mainly incorporating the TCXO compensation circuit into an IC, but there are the following problems in implementing the IC. It was That is, the above TC
Not only when the XO is integrated into an IC, a voltage regulator circuit that stabilizes a power supply voltage having an arbitrary nominal value within a predetermined range to a predetermined voltage value and supplies it to an analog portion such as an oscillation circuit is required. Due to variations in the manufacturing process, it has been difficult to manufacture the regulator circuit with a high precision of, for example, ± 0.1V. Further, it is impossible to adjust the inside by a method such as laser trimming as in a commercially available single IC. Therefore, in the past, the TCXO
When integrated into an IC, it was difficult to provide a voltage regulator circuit that supplies a highly accurate stabilized voltage.

[0004]

[Object] The present invention has been made in view of the above circumstances, and is a case in which a temperature-compensated oscillator (TCO) can be integrated into an IC to be remarkably downsized, and the TCO can be downsized by IC. Even if it aims at providing the voltage regulator circuit which can supply a highly accurate stabilized voltage, and TCO using the same.

[0005]

In order to achieve the above object, the invention of claim 1 is a voltage or current regulator circuit for supplying a stabilized power supply, which is an amplifier or a control element for controlling an output voltage or current. A resistance circuit network including a plurality of resistance groups and switch groups is provided as a resistance circuit that determines the amplification degree, and a desired voltage or current is output by externally controlling the ON / OFF combination of each switch of the switch groups. It is characterized in that it is configured to. The invention of claim 2 is a voltage or current regulator circuit for supplying a stabilized current, wherein an amplifier for controlling the output voltage or current is a differential amplifier, and a plurality of resistance circuits for determining the amplification factor are provided. The present invention is characterized in that a resistance circuit network including a resistance group and a switch group is provided, and a desired voltage or current is output by externally controlling a combination of ON / OFF of each switch of the switch group. Claim 3
In the invention, the switch group in the resistance circuit is a semiconductor circuit. The invention of claim 4 is characterized in that the switch group in the resistance circuit is a semiconductor switch circuit, and ON / OFF information thereof is stored in a memory circuit. At least a part of the invention of claim 5 is an IC.
In a temperature-compensated oscillator that has been integrated, a plurality of resistance groups and switch groups are formed as a resistance circuit that determines the amplification degree of an amplifier or a control element that controls the voltage / current of a voltage regulator circuit for supplying stabilized power. It is characterized by comprising a resistance circuit network and a memory storing information for turning ON / OFF the switch group.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on the illustrated embodiments. FIG. 1 is a configuration block diagram showing an example of an IC temperature compensated crystal oscillator (TCXO) having an embodiment of a TCXO to which a voltage dividing circuit according to the present invention is applied. As shown in FIG. 1, the TCXO is an integrated IC unit 6 having a compensation circuit unit and an oscillation circuit unit for generating a specific functional voltage with respect to the temperature axis.
A varicap portion 7 externally connected to the IC portion 6, and a crystal resonator 8 connected to the varicap portion 7.
And a configuration having: The thermistor section 9 of the compensation circuit is externally connected to the IC section 6,
A DC voltage of a cubic function of temperature is generated with a change in temperature. The IC unit 6 includes an input / output terminal group 10 for inputting and outputting various signals for adjusting and measuring temperature compensation, a switching circuit 11 connected to the terminal group 10,
Memory connected to the switching circuit 11 (EE-PRO
M) 12, a voltage regulator circuit 13 connected to the memory 12, a variable resistance network 14 connected to the switching circuit 11 and the memory 12, the thermistor section 9 and the varicap section 7, and the switching circuit 11 and Voltage dividing circuit 1 connected to the memory 12 and the varicap unit 7.
5 and the oscillation circuit 16 connected to the varicap portion 7
An output buffer 18 connected to the oscillation circuit 16 and the output terminal 17, the switching circuit 11 and the memory 1
2 and power supply terminals 19 and 20 connected to the voltage regulator circuit 13.

Next, the manufacturing process of the TCXO, particularly the outline of the adjustment will be described with reference to the operation flowchart of FIG. 2. First, in step 100, the temperature characteristic before compensation is measured. As a result of this measurement, frequency deviation data at each temperature is acquired, and the voltage division of the voltage dividing circuit 15 and the temperature characteristic of the variable resistance circuit network 14 are transferred from the terminal group 10 to the memory 12 via the switching circuit 11. Correction data including correction of variations in the output voltage of the voltage regulator circuit 13 is written (step 101). Next, step 10
In 2, the compensation operation is actually performed to measure the output frequency at each temperature and the voltage of each part if necessary. As a result, if the temperature temperature characteristic of the frequency is within the specified value, the adjustment is ended, but if the standard value is not satisfied (NO in step 103), the correction data is further partially stored based on the measurement result. Write to 12 (step 104). In the actual operation, the TCXO that has undergone such adjustments reads the adjusted correction data from the memory 12, and needs the correction data to correct the temperature characteristics and the variation in the output voltage. It is sent to each part (the switching circuit 11, the voltage regulator circuit 13, the variable resistance circuit network 14, the voltage dividing circuit 15) in the IC unit 6 which is activated. Further, during use, the user may adjust the AFC sensitivity by the voltage dividing circuit 15.

Next, the voltage regulator circuit 13 which is the main part of the present invention will be described. The voltage regulator circuit 13 shown in this example stabilizes the power supply voltage of any nominal value (stability within ± 10%) in the range of +3.0 to +5.0 V to +2.5 V, and the oscillation circuit 16 described above. And for supplying to an analog circuit such as the output buffer 18 and the characteristic of this configuration is that the output voltage is set to the FET 2 as shown in FIG.
The gate voltage is controlled by the differential amplifier 23, and the gate voltage is controlled by the differential amplifier 23. The ROM data from the memory 12 is referred to as a resistance circuit for determining the amplification factor of the differential amplifier. That is, the resistance voltage (trimming circuit) 24 whose resistance value is determined is used, and the stabilization voltage can be finely adjusted by the ROM data. This will be described in more detail with reference to FIG. 3. This voltage regulator circuit 13 has a reference voltage (V _ref ) on the input terminal V _IN side.
The circuit 21 is connected, and the input terminal V _IN and the output terminal V are connected.
The first FET 22 is connected between _OUT , and the first F
The output side of the differential amplifier 23 is connected to the gate side of the ET 22. A trimming circuit 24 for finely adjusting (trimming) the stabilized output voltage is connected to the + input terminal of the differential amplifier 23, and the V _ref circuit is connected to the-input terminal of the differential amplifier 23. 21 outputs are provided.

The V _ref circuit 21 has second and third FETs 25 and 26 connected in series, the source side of the second FET 25 being connected to the input terminal V _IN, and the second The drain side of the FET 25 is connected to the source side of the third FET 26, and the second and third FETs
The gate sides of the FETs 25 and 26 are connected to each other, and are connected to the drain side of the second FET 25, the source side of the third FET 26 and the-input terminal of the differential amplifier 23. In addition, the above-mentioned third FET
The drain side of 26 is connected to ground. Further, a first resistor 27 is connected between the + input terminal of the differential amplifier 23 and the output terminal V _OUT . The trimming circuit 24 has a resistance value of the memory 1
It can be changed by adjusting data (ROM data) from No. 2, and after the second resistor 28,
A plurality of pairs of a resistor 29 and a switch 30 connected in parallel between the resistor 28 and the ground are connected in a ladder shape. The resistance value of the trimming circuit 24 is changed by controlling the opening and closing of the switch 30 according to the adjustment data from the memory 12. The switch is, for example, a semiconductor switch, and a voltage or current is supplied by a signal line (not shown) so that an arbitrary or required switch can be turned on or off.

The operation of the voltage regulator circuit will be described. When an input voltage is supplied from the input terminal V _{IN, a} reference voltage is first generated from the V _ref circuit 21 and supplied to one input of the differential amplifier 23. FET22 becomes conductive,
V _{OUT of the} differential amplifier is output. At this time, the drain-source resistance of the FET is small and V _IN is almost V
This is _OUT , but this V _OUT voltage is the resistance 2 on the FET output side.
7 and the resistors 28 and 29 of the trimming circuit, and the divided voltage is supplied to the + input of the differential amplifier 23. As a result, the divided voltage determined by the dividing ratio of these resistors and the V _ref circuit output voltage. V determined by the relationship with
_{The OUT} value is obtained. Therefore, the divided voltage value changes depending on which of the switches of the trimming circuit 24 is turned on, and thus V _OUT changes. On the other hand, these voltage / current regulators or other load circuits formed as an IC as described above have a large manufacturing error, and V _OUT often deviates from a desired value. Alternatively, even if V _OUT reaches a desired value, it may be necessary to slightly change V _OUT depending on the variation in the characteristics of the load circuit to which the power supply circuit should supply power. Therefore, in this embodiment, the trimming circuit 24 is adjusted by the adjustment data from the memory 12.
The stable value voltage is adjusted by adjusting the amplification ratio of the operation amplification by adjusting the resistance value of. Therefore, a highly accurate predetermined stabilizing voltage can be obtained.

That is, a signal (not shown) is operated by operating the manufactured IC circuit? Via the regulator output voltage V
_{If OUT} is measured and it is different from the specified value, trimming circuit 2
The desired output voltage is obtained by changing the switch that turns on the switch 30 of No. 4. Then, the switch ON / OFF information at that time is stored in the ROM. After that, when the power is turned on, the switch ON / OF stored in the ROM is turned on.
The switches of the trimming circuit 24 are controlled based on the F information to obtain a desired voltage. Note that the regulator circuit is a current regulator that generates a constant current as well as voltage.
Is also known, and in the same manner as the present invention, the current regulation
It goes without saying that it can be applied to a computer.

[0012]

As described above, according to the present invention, in a voltage regulator circuit for supplying a stabilized power source in an integrated TCXO, in a regulator circuit configured to control an output voltage / current by a differential amplifier, its amplification. Since the resistance circuit network (trimming circuit) whose resistance value is determined by referring to the data stored in the memory is used as the resistance circuit that determines the rate, the output voltage due to the manufacturing error that generally occurs when integrated into an IC. It is possible to finely adjust the stabilizing voltage by the ROM data so as to easily correct the variation of the above.

[Brief description of drawings]

FIG. 1 is an integrated temperature compensated crystal oscillator (TCX) having an embodiment of a voltage regulator circuit according to the present invention.
It is a configuration block diagram of (O).

FIG. 2 is a flowchart of a method for adjusting the TCXO shown in FIG.

FIG. 3 is an internal configuration diagram of the voltage regulator circuit shown in FIG.

FIG. 4A is a conventional temperature-compensated crystal oscillator (TCX).
It is a basic block diagram of (O), (b) is a block diagram of the compensation circuit shown in (a).

[Explanation of Codes] 1 ... Compensation circuit, 2 ... Varactor diode (varicap), 3, 8 ... Crystal oscillator, 4, 16 ... Oscillation circuit (OS
C), 5 ... Capacitor, 6 ... IC part,
7 ... Varicap part, 9 ... Thermistor part, 10 ... Input / output terminal group, 11 ... Switching circuit, 12 ...
Memory (EE-PROM), 13 ... Voltage regulator circuit, 14 ... Variable resistance network, 15 ... Voltage dividing circuit, 17 ... Output terminal, 18 ...
Output buffer, 19, 20 ... Power supply terminal, 21 ... Reference voltage circuit, 22
... first FET, 23 ... operational amplifier,
24 ... Trimming circuit, 25, 26 ... 2nd and 3rd FET, 27 ... 1st resistance, 28 ... 2nd resistance, 29 ... Resistance, 30 ... Switch, 100-104 ... Each step,

Claims (5)

[Claims] 1. A voltage or current regulator circuit for supplying stabilized power, comprising a plurality of resistance groups and switch groups as a resistance circuit for determining the amplification degree of an amplifier or a control element for controlling an output voltage or current. A voltage / current regulator circuit comprising a resistance circuit network and configured to output a desired voltage or current by externally controlling a combination of ON / OFF of each switch of the switch group. 2. A voltage or current regulator circuit for stabilizing current supply, wherein an amplifier for controlling an output voltage or current is a differential amplifier, and a plurality of resistor groups are used as a resistor circuit for determining its amplification factor. And a resistor circuit network composed of a switch group, and is configured to output a desired voltage or current by externally controlling a combination of ON / OFF of each switch of the switch group. Regulator circuit. 3. The voltage / voltage according to claim 1, wherein the group of switches in the resistance circuit is a semiconductor circuit.
Current regulator circuit. 4. The voltage / voltage according to claim 3, wherein the switch group in the resistance circuit is a semiconductor switch circuit, and ON / OFF information thereof is stored in a memory circuit.
Current regulator circuit. 5. A temperature-compensated oscillator, at least a part of which is integrated as an IC, as an amplifier for controlling voltage / current of a voltage regulator circuit for supplying a stabilized power supply, or as a resistance circuit for determining an amplification degree of a control element. A resistor network composed of a plurality of resistor groups and a switch group, and ON / OFF of the switch group.
A temperature-compensated oscillator, comprising: a memory that stores information to be turned off.